Hydroxy fatty acid (HFA) is a compound where one or more hydroxyl groups are linked to the main chain of fatty acid. These hydroxyl groups endow specific characteristics including high viscosity or reactivity to fatty acid. According to the specific characteristics generated by the hydroxyl group, HFA exhibits various physiological functions so that it can be applied in the wide range of industrial fields including novel pesticides, novel medicines, high-functional resins and fibers, biodegradable plastic materials, lubricants, cosmetics, paints, etc. Ricinoleic acid, a derivative of castor oil, or sebacic acid has been used as a synthetic material for highly efficient polymer having new function so far, and this material is classified as ‘industrially essential material’ by US government. According to the number of hydroxyl groups linked to HFA, it is classified into mono-, di- and tri-hydroxy fatty acid and epoxy-hydroxy fatty acid or oxo-hydroxy fatty acid having an extra structure besides hydroxyl group are also included in this family.
Although many functions of hydroxy fatty acid have been known, only a minute amount of hydroxy fatty acids exists in plants in natural system. So, there have been attempts to produce hydroxy fatty acids using microorganisms. Flavobacterium sp DS5 has been reported to be able to produce 10-hydroxy-octadecadienoic acid from oleic acid, and such a production was presumably mediated by 10-specific hydratase. It was also reported that Pseudomonas aeruginosa PR3 could produce mono-, di- and tri-hydroxy fatty acid using wide range of substrates.
The present inventors completed this invention by identifying the compound produced by a microorganism using natural vegetable oil as a substrate to be 7,10-dihydroxy-8(E)-octadecenoic acid and further by confirming that this compound had antibacterial activity.